1
Aminoacid-derived Cu
II
compounds as catalysts for asymmetric
oxidative coupling of 2-naphthol
P. Adão, S. Barroso, M. F. N. N. Carvalho, C. M. Teixeira, M. L. Kuznetsov, J. Costa Pessoa
1
Centro Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av.
Rovísco Pais, 1049-001 Lisboa, Portugal
Supporting Information
Synthesis of ligand precursors
(S)-3-phenyl-2-(pyridin-2-ylmethylamino)propanoic acid, H1. L-phenylalanine (L-Phe,
3.4 g, 20 mmol) and NaOH (0.8 g, 21 mmol) were added to 40 mL of ethanol (EtOH).
After the dissolution of the amino acid, pyridine-2-carboxaldehyde (2.2 g, 1.9 mL, 20
mmol) was added. After 30 minutes of stirring, approximately 1 g of NaBH
4
was
carefully added to the mixture. After the gas evolution mostly subsided, the pH was
carefully adjusted to ca. 2 with conc. HCl to decompose excess NaBH
4
. The pH was
readjusted to ca. 7 with saturated aqueous NaHCO
3
and a white solid precipitated. The
solid was filtered and washed with water and diethyl ether. Yield: 68 % (3.5g)
1
H-NMR
(300 MHz, D
2
O + MeOH marker, excess Na
2
CO
3
, ppm): 2.90 [2H, m, -CH
2
CHCOONa],
3.36 [1H, m, -CH
2
CHCOONa-, signal masked by MeOH, detected by HSQC], 3.64 [1H,
d,
2
J
HH
=13.9 Hz, PyCHHNH-], 3.81 [1H, d,
2
J
HH
=13.9 Hz, PyCHHNH-], 7.20 to 7.35
[7H, m, aromatic], 7.74 [1H, td, J
1
=7.7 Hz, J
2
=1.5 Hz, aromatic], 8.37 [1H, d,
3
J
HH
=4.5
Hz, aromatic].
13
C-{
1
H} NMR (75 MHz, D
2
O + MeOH marker, excess Na
2
CO
3
, ppm): δ
39.73 [1C, -CH
2
CHCOONa], 52.68 [1C, PyCH
2
NH-], 65.48 [1C, -CH
2
CHCOONa],
123.49, 123.55, 127.22, 129.16, 129.83, 138.62, 138.68, 149.96, 158.14 [11C, aromatic],
181.06 [1C, -COONa]. Elemental analysis for C
15
H
16
N
2
O
2
: C 70.29, H 6.29, N 10.93;
found: C 70.0, H 6.4, N 11.0.
(R)-3-phenyl-3-(pyridin-2-ylmethylamino)propanoic acid, H2. The preparation method
for this compound was identical to that used for 1. Reagents: L--phenylalanine (L--
Phe, 3.3 g, 20 mmol), pyridine-2-carboxaldehyde (2.1 g, 1.9 mL, 19 mmol), NaOH (0.8
Electronic Supplementary Material (ESI) for Dalton Transactions.
This journal is © The Royal Society of Chemistry 2014